A descarga de medicamentos ou contraceptivos como a “pílula”, antibióticos, anti-depressivos (entre outros medicamentos e produtos químicos) via águas pluviais, ou comum “WC”.

O tratamento das nossas ETAR´s pode não ser efectivo contra a remoção destes productos e afectar fortemente quer as populações de peixes como outros animais tais como as tartarugas, citando esta noticia publicada.(ver em baixo)

O estrogénio (hormona feminina) e seus derivados é muitas vezes utilizado em aquacultura para controlar o ratio machos/fêmeas na produção.

Escusado será dizer que a descarga indiscriminada de águas onde estão dissolvidos estes agentes químicos induz a grandes modificações quer a nível sexual, ou,como no caso de antibióticos, deprimindo o sistema imunitário de um largo espectro de espécies marinhas e dulceaquícolas.

mais info: Dairy Wastewater, Aquaculture, and Spawning Fish as Sources of Steroid Hormones in the Aquatic Environment

ENVIRONMENT: Household Chemicals Wreaking Havoc in Fish
By Adrianne Appel

Some trout populations fell by a third after estrogen was introduced into the water.

Credit:pxlpusher

BOSTON, United States, Feb 26 (IPS) – When people take their daily doses of birth control pills, antidepressants and antibiotics, fish are being dosed too.

“What you probably haven’t heard is the [contraceptive] pill is just as effective in controlling reproduction in fish as in humans,” said Karen Kidd, a scientist at the University of New Brunswick, Canada.

A fast-growing body of research is proving how everyday drugs, cosmetics, pesticides and chemicals from plastics and flame retardants are not stopped by typical wastewater treatment, and so flow out into oceans, lakes, rivers and streams.

Fish and turtles swim in a constant bath of these low levels of hormones, drugs and chemicals and studies show they harm reproduction and immune systems.

More than 100 million women worldwide take birth control pills, Kidd said. In addition, common ingredients in shampoos and plastics act like estrogens when they are ingested by humans, animals and plants.

“There are thousands of pharmaceuticals we take. They get flushed down our toilets and out to wastewater treatment plants,” said Kidd.

The technology exists to nearly completely eliminate many drugs and hormones from wastewater and it is not sophisticated, Kidd said. Upgrading from what is known as secondary sewage treatment to tertiary treatment would remove estrogen and many drugs. Most cities have not done this, however.

In Kidd’s study, the female hormone estrogen was added to a pristine Canadian lake over a three-year period, in amounts commonly found in wastewater. By the second year, male fathead minnows were found to be growing female eggs. The tiny minnow is about the size of a pinky and lives for two years.

“What was surprising was how quickly the fathead minnow was affected. It shows that short-lived fish are at the greatest risk,” Kidd said. By year two, their population plummeted and 99 percent was lost. Those that survived were ones that were not spawning, so they grew larger than normal and lived longer.

[...]

“Studies like these force us to see the whole picture and to make connections not only between land and sea but also how what we put in or on our bodies or use in homes can affect our world,” said Sotka, who works with the U.S. National Oceanic and Atmospheric Administration.

Scientist Steven Bay has seen similar problems in the fish off the coast of California, which are exposed to hormones and chemicals that enter the ocean in water from wastewater treatment plants.

[...]
Another study found that loggerhead turtles, which live off the East Coast of the U.S., are being harmed by the chemicals used to repel stains on carpets, called PFCs.

The chemicals are absorbed by mussels and clams, which are eaten by the turtles. The chemicals accumulate in the turtles and wreak havoc with their livers and immune systems, Keller said.

“They get into the environment through normal wear and tear,” said Jennifer Keller, a scientist with the U.S. National Institute of Standards and Technology

“Chronic exposure to contaminants may impair their defences against disease or their ability to reproduce,” Keller said, adding that humans have similar immune systems and so also may be at risk of health problems from exposure to PFCs.

“The PFC levels in the turtles are equal to the levels found in humans,” she said.

(END/2008)

source: www.ipsnews.net